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Re: [css3-background] box-shadow syntax

From: Henrik Hansen <henrikb4@gmail.com>
Date: Sun, 11 May 2008 11:36:31 +0200
Message-ID: <dd12cf660805110236k4db1d161gfaa2dee098c0d321@mail.gmail.com>
To: "Alan Gresley" <alan@css-class.com>
Cc: www-style@w3.org
Alan Gresley wrote:

> Precisely
>
> A glass top outdoor table will cast a shadow since the glass is reflecting
> some of the light upwards but at the same time you can view this shadow cast
> by the glass through the glass top table itself. Shadow naturally can be
> seen through transparent surfaces such as a transparent background. This is
> seen to the two examples on the second row in your screenshot Henrik.
>
> I do remember David Hyatt mentioning in Jan~Feb how shadows can be
> painted. There was two ways of doing it. One was easier. Now I can't find
> the link.



Hmm, one way of making shadow maps are by taking the Alpha-layer of the
object and using that as the shadow map. It's a quick way and it can be
optimized in various kinds of ways.
Furthermore, By taking the RGB values of the image and masking it with the
Alpha-layer, you can also make the "transmittance" effect. Again, it can be
optimized by using some tricks.

I'm sure that there exist other ways, but I could only come up with this
one.

-Henrik Hansen

P.s. I make a diagram of my idea when I get to my own computer.
Received on Sunday, 11 May 2008 10:39:09 GMT

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